Case-control study of risk factors for mediastinitis after cardiovascular surgery.

We report results of a case-control study in which we evaluated 41 risk factors potentially associated with the development of postsurgical mediastinitis. There were 163 case patients and 326 control patients. Independent risk factors kept in the final multivariate logistic regression model were obesity (defined as a body mass index of greater than 30), diabetes mellitus, chronic obstructive pulmonary disease, preoperative stay longer than 1 week, pulmonary hypertension, perioperative myocardial infarction, and reoperation.

Accuracy of blood culture for early diagnosis of mediastinitis in febrile patients after cardiac surgery.

Postsurgical mediastinitis (PSM) remains a major cause of morbidity and mortality in patients undergoing cardiac surgery procedures. Although prompt diagnosis is crucial in these patients, neither clinical data nor imaging techniques have shown enough sensitivity or specificity for early diagnosis of PSM. The aim of the present study was to assess the validity of blood cultures as a diagnostic test for the early detection of PSM in patients who become febrile after cardiac surgery procedures. During a 4-year period (1999-2002), patients who developed fever (>37.8 degrees C) in the first 60 days after a cardiac surgery procedure were evaluated. Blood cultures were drawn from these patients. PSM was defined as deep infection involving retrosternal tissue and/or the sternal bone directly observed by the surgeon and confirmed microbiologically. Three criteria for positivity of blood cultures were applied: bacteremia, staphylococcal bacteremia, or Staphylococcus aureus bacteremia. For purposes of the analysis, a positive blood culture in patients with PSM was considered a true-positive test and a negative blood culture a false-negative test. Otherwise, in febrile patients without PSM in the postsurgery period, a positive blood culture was considered a false-positive test and a negative blood culture a true-negative test. Blood cultures were drawn from 266 febrile patients in the postsurgery period. PSM occurred in 38 patients (26 cases due to S. aureus, 8 to Staphylococcus epidermidis, 3 to gram-negative enteric bacteria, and one to Pseudomonas aeruginosa). Within the 60-day postsurgical period, blood culture as a diagnostic test was most accurate in patients with S. aureus bacteremia, providing 68% sensitivity, 98% specificity, a positive predictive value of 87%, and a negative predictive value of 95%. If the analysis was limited to the period during which patients are at maximum risk for PSM (day 7-20), the values in patients with S. aureus bacteremia were as follows: 73% sensitivity, 98% specificity, 90% positive predictive value, and 93% negative predictive value. Blood culture is an accurate test for the early diagnosis of PSM in febrile patients after cardiac surgery, particularly in institutions where S. aureus is prevalent in this context. A negative blood culture practically excludes PSM and, during the period of maximum risk for PSM, the presence of S. aureus bacteremia should compel early surgical management.

Impact of mild pulmonary hypertension on mortality and pulmonary artery pressure profile after heart transplantation.

BACKGROUND: Pulmonary hypertension is a risk factor for early mortality after transplantation, but the risk threshold is debated. Also, little is known about the evolution of pulmonary circulation after transplantation. The aim of this study was to determine the influence of current risk pulmonary pressure parameters on early post-operative mortality and to assess the time-related changes in pulmonary pressure after surgery. METHODS: One hundred twelve consecutive transplanted patients were studied retrospectively to determine the influence of trans-pulmonary gradient of >12 mm Hg and pulmonary vascular resistance of >2.5 Wood units, at baseline or after vasodilator test, on early mortality. A multivariate analysis was used to study the hemodynamic parameters associated with early mortality. The pulmonary pressures of all surviving patients were studied for up to 3 years after surgery. RESULTS: Early mortality in the groups with and without pulmonary hypertension were 24.4% and 5.6%, respectively (p =.009). The only variable that was independently associated with early mortality was the pulmonary vascular resistance index (odds ratio = 1.459). Mild pulmonary hypertension disappeared 1 year after heart transplantation. CONCLUSIONS: Mild pulmonary hypertension is a risk factor for early postoperative mortality. The hemodynamic parameter most closely associated with early mortality is pulmonary vascular resistance index. The hemodynamic profile of pulmonary circulation after heart transplantation is partially dependent on the level of pulmonary hypertension before transplantation, at least during the first year after surgery.

[Surgical reconstruction of intervalvular fibrous body in active infective endocarditis]. / Cirugía de reconstrucción del cuerpo fribroso intervalvular en la endocarditis infecciosa activa.

INTRODUCTION AND OBJECTIVES: Surgery for infective endocarditis with paravalvular abscesses and fibrous body destruction has the highest mortality and morbidity rates in this disease with high surgical risk. We report a new approach of radical resection of the abscess and affected tissues and reconstruction of the heart with pericardium as an alternative to conventional surgery. METHODS: In the last two years six patients with infective endocarditis, paravalvular abscesses and fibrous body destruction underwent surgery (five prostheses with infective endocarditis). The main indication for surgery was persistent sepsis despite adequate antibiotic treatment in five patients and congestive heart failure in one. After wide resection of the abscesses and fibrous body the heart was reconstructed with glutaraldehyde-fixed bovine pericardium. RESULTS: There was no hospital mortality. The median bypass and clamp times were 198 and 174 minutes, respectively. One patient presented complete AV block and a permanent transvenous pacemaker was implanted. Doppler echocardiographic studies performed in all the patients prior to discharge indicated that no patient had patch dehiscence or paravalvular leaks. Patients were followed a mean of 15 months with no deaths or other complications being reported. CONCLUSIONS: Resection of the abscesses and fibrous body, and reconstruction of the heart with glutaraldehyde-fixed bovine pericardial patch is a radical, feasible technique with all infected tissues being resected to thereby prevent reinfection or paravalvular leaks.

[Early results with partial left ventriculectomy (the Batista operation)]. / Resultados precoces de la ventriculectomía parcial izquierda (operación de Batista).

INTRODUCTION AND OBJECTIVES: The shortage of donors as well as the morbidity and mortality associated with transplantation have led to development of other surgical options for end-stage dilated cardiomyopathy. Partial left ventriculectomy reducing ventricular diameter and mass has been proposed. We here in report the initial experience (not only limited to the alternative of transplantation) and immediate results obtained with this technique in our institution. METHODS: Six patients with dilated cardiomyopathy underwent surgery: 4 of idiopathic origin with exclusion criteria for heart transplantation and 2 of valvular or mixed etiology. Resection of a slice of the left ventricle was performed between the two papillary muscles, from the apex of the heart to the mitral annulus, and closure was carried out with a single suture with mitral annuloplasty in 5 cases (tricuspid repair in one and aortic valve replacement in two). RESULTS: An intraaortic balloon pump was required in two patients; one died from cardiogenic shock and the other died after several ventricular arrhythmias fifteen days after surgery. Intraoperative echocardiographic studies showed a significant reduction in both diastolic diameter (8.7 to 6.8 cm; p = 0.02) and mitral insufficiency and an increase in the ejection fraction (17 to 27%; p = 0.09) which were maintained on echography 10 days after surgery. CONCLUSIONS: This technique is a feasible, suitable therapeutic option for refractory congestive heart failure. Appropriate patient selection, the perioperative management and long-term support remain to be defined.

Neurological complications after cardiopulmonary bypass: An update.

INTRODUCTION: Neurological complications are, at the present time, considered among the most important causes of morbidity and mortality after heart surgery. We evaluated their importance and risk factors. PATIENTS AND METHODS: We retrospectively reviewed 2, 528 consecutive patients who underwent cardiopulmonary bypass in a single center. In each one, we attended to previous vascular risk factors, such as surgical and postoperative events. We considered four categories of neurologic outcome: (1) persistent neurological focal deficits, (2) stupor or coma, (3) temporary neurological focal deficits, and (4) seizures. We carried out univariant and multivariant statistical analysis, looking for predictors of adverse neurologic events. RESULTS: Neurological complications occurred in 76 patients (3%); 36 of them (47%) had persistent neurological focal deficits, 18 (24%) stupor or coma, 18 (24%) temporary neurological focal deficits, and 27 (36%) seizures. Twenty-two patients with cerebral adverse outcomes died (29%), the overall mortality among the 2,528 cases being 5%. Predictors of risk were aortic aneurysm and aortic valve surgery, advanced age, female sex, and the use of intra-aortic balloon pump. A longer hospitalization time was noticed among patients with neurological side effects. DISCUSSION: Neurological complications are common and serious after heart surgery, as we have noticed with this series, the largest up to now, according to our review of the literature. They increase perioperative mortality and hospitalization time. Neurological morbidity and risk factors in our study are similar to those previously published.

[Neurological complications of aortic artery surgery]. / Complicaciones neurológicas de la cirugía de la arteria aorta.

INTRODUCTION: Improvement in cardiac surgery techniques has led to a considerable reduction in mortality following surgery of the aorta, dissection of the aorta and for aortic aneurysms. Although there are satisfactory vascular results following surgical repair, morbi-mortality related to neurological complications, both cerebral and spinal, is still very high. Repair of aortic lesions may lead to damage by two main mechanisms: ischemia secondary to prolonged obstruction of the aorta or to neurological lesions due to total circulatory arrest. DEVELOPMENT: After description of the mechanisms leading to cerebral and spinal lesions and the risk factors involved, we discuss methods of vascular protection and other means of neuro-protection, both spinal and cerebral. Of the vascular techniques for spinal protection, the most useful ones are short-circuits, or active or passive shunts, and cardiopulmonary by-pass. Amongst the vascular techniques for cerebral protection we describe total circulatory arrest and methods of anterograde and retrograde cerebral perfusion, and when these may be used. As general measures for nervous system protection, we describe the use of hypothermia and drugs such as corticosteroids, free radical blockers, antagonists of the excitatory amino-acids etc. CONCLUSIONS: In spite of the number of studies done, the extreme sensitivity of the nervous system to ischemia has meant that in few cases have encouraging results been seen. Neurological damage continues to be the main cause of morbi-mortality in patients with dissection or aneurysm of the aorta.

A new approach to cardiac valve replacement through a small midline incision and inverted L shape partial sternotomy.

OBJECTIVE: Minimally invasive cardiac surgery is becoming more popular as an alternative technique in some cardiac operations. We report our experience with an inverted 'L' ministernotomy in 25 patients and describe the technical details of this new approach. METHODS: From June 1996 to February 1997 we performed 25 ministernotomy approaches for cardiac surgery, 17 aortic and 7 mitral valve replacements and 1 atrial septal defect closure. A comparison group included all patients (n = 126) operated on for mitral or aortic valve replacement through a median sternotomy since June 1996. RESULTS: Ventilatory support, Intensive Care Unit stay and hospital stay were 8.3 h (SD = 4 h), 25 h (SD = 8 h) and 5.5 days (SD = 3 days) in the L ministernotomy group and 11.5 h (SD = 5), 53 h (SD = 11) and 9.1 days (SD = 4 days) in the median sternotomy group (P < 0 05). Mortality and morbidity are similar to conventional sternotomy (hospital mortality 4% vs. 5.5%; P not significant). CONCLUSIONS: We conclude that inverted L ministernotomy for cardiac surgery is a safe approach and can offer some advantages over the conventional approach.

[Scales of risk assessment in coronary surgery and their usefulness]. / Escalas de valoración de riesgo en cirugía coronaria y su utilidad.

Currently, there is an increasing interest in the fields of cardiology and cardiac surgery related to systems of risk assessment of cardiac surgery procedures. The main benefit of these systems is quality control of results obtained. Nevertheless, there are other interesting implications. Currently, most of the available scales make estimations of mortality risk with a defined operative technique, using preoperative variables. Other systems can make predictions on postoperative length of stay. Scales are built using the results of a large series, processed with different mathematical models. An important condition is the simplicity of use. There is a wide range of available systems originating from clinical experience in Europe and North-America. All of them include a common number of predictive factors, although the assigned weight can vary significantly. We recommend the routine use of these scales as a quality control system and as a method of characterization of our populations in order to make adequate comparisons among different groups.

[The etiology of neurological complications after cardiopulmonary bypass surgery]. / Etiología de las complicaciones neurológicas tras cirugía extracorpórea.

INTRODUCTION: Cardiopulmonary bypass (CEC) in the surgical treatment of cardiac diseases may cause the appearance of neurological damage of an intensity which varies between minor neuropsychological disorders and global cerebral anoxia. There are two mechanisms for the production of these lesions: ischaemic and embolic. The mortality associated with this type of complication is low, but morbidity may be considerable. The neurological disorders derived from CEC may be classified according to the aetiology and clinical findings. In the first group are included: severe cerebral anoxia, embolic cerebro-vascular accidents, microvascular embolias, lesions of spinal vascularization and lesions of the peripheral nerves. In the second group are: encephalic focal lesions, convulsive crises, lesions of the extra-pyramidal system, alterations in the level of consciousness and neuropsychological disorders. METHODS: Quantification of neuronal damage has been attempted by: monitoring cerebral blood flow and neurone metabolism, EEG and study of intra-operative evoked potentials, echography of the carotid, cardiac and ascending aorta, transcranial doppler, fluorescein-angiography and the study of biochemical markers of neuronal and glial damage. Different studies have identified a series of factors which potentiate the risk of neurological lesions following CEC. These are: age, severe carotid disease, aortic atherosclerosis and previous cerebro-vascular haemorrhage, amongst others. An attempt is made to reduce the incidence of neurological complications by: pre-operative evaluation of carotid bruits, hypothermia, careful surgical technique and the use of drugs with a neuroglial protector effect. None of these methods gives sufficiently effective protection to the central nervous system subjected to the changes involved in the use of CEC. CONCLUSION: There are still many unknown aspects of neurone pathology in these circumstances, leaving a door open to investigation.

Role of epicardial pacing wire cultures in the diagnosis of poststernotomy mediastinitis.

Mediastinitis after cardiac surgery is difficult to diagnose in many cases. The transitory epicardial pacing wires used after surgery are placed in the mediastinum, so the culture of these wires could be useful for the diagnosis of this disease. To test this hypothesis, we routinely cultured the epicardial pacing wires of 565 patients undergoing extracorporeal circulation. Wires were removed on the 7th to 9th postoperative day under sterile conditions and were cultured with routine techniques used for the culture of venous catheters. Mediastinitis developed in 16 patients, and Staphylococcus aureus was the most common pathogen (81.25%). We had 103 positive and 462 negative cultures. There were 458 true-negative, 12 true-positive, 91 false-positive and 4 false-negative results. For mediastinitis in general, epicardial pacing wire culture has a sensitivity of 75%, specificity of 83.4%, positive predictive value of 11.6%, and negative predictive value of 99.1%. For Staphylococcus aureus mediastinitis, epicardial pacing wire culture has a sensitivity of 84.6%, specificity of 95.8%, positive predictive value of 32.3%, and negative predictive value of 99.6%. We conclude that a sterile culture of the epicardial pacing wires strongly contradicts a diagnosis of postsurgical mediastinitis.

Intracardiac thrombus trapped in a patent foramen ovale.

We describe a case of impending paradoxical embolism due to a thrombus trapped in a patent foramen ovale in a 22-year-old woman. Transthoracic and transesophageal echocardiography detected the thrombus. She was operated on and discharged asymptomatic.

[Aortic valve replacement via ministernotomy]. / Sustitución valvular aórtica por miniesternotomía.

Minimally invasive cardiac surgery is arising as an alternative technique in some cardiac operations. We present the first aortic valve replacement via ministernotomy. We describe in detail the technique of ministernotomy and the limitations that this new approach would have. We conclude with the advantages of minimally invasive cardiac surgery over conventional approach and review other techniques described in the literature.

[Infection of sternal wound in heart surgery: analysis of 1000 operations]. / Infección de la herida esternal en la cirugía cardíaca: análisis de 1.000 intervenciones.

BACKGROUND: Sternal wound infection (SWI) is the most important complication in cardiac surgery. The aim of this study was to describe the frequency and clinical and microbiological features of this complication. METHODS: All the cases of SWI which were observed in the authors' hospital in the first 1,000 cardiac surgery operations performed with extracorporeal circulation were retrospectively reviewed. The cases were identified through the Infectious Diseases and Cardiac Surgery Department files and were classified according to the depth of the infection. During the study period neither the prophylaxis against infection nor the surgical techniques were modified. RESULTS: Forty-three patients (4.3%) presented SWI. Fourteen were superficial infections and 29 were deep infections of which 9 were classified as osteomyelitis and 20 as mediastinitis. A progressive decrease was observed in the proportion of SWI over time parallel to an increase in the number of operations performed. Staphylococcus aureus was the agent most frequently isolated (60.4%). Gram-positive aerobic cocci were found in 66.7% of the total number of isolations, being most frequent in the deep infections (83.3% of the isolations). The gram-negative aerobic bacilli were isolated more frequently in the superficial infections than in the deep infections (57.8% v.s. 16.7% of the isolations, respectively p < 0.01). In patients with SWI the predictive value of the positive blood cultures for the diagnosis of mediastinitis was 83.3%, with a sensitivity of 50% and specificity of 91.3%. Three patients with deep infection developed chronic complications and another three died (mortality by mediastinitis 15.0%). The mean postoperative stay was 52 days for the patients with deep infection and 39 days for those with superficial infection (p = NS). CONCLUSIONS: The percentage of surgical wound infection during the study period showed a trend to a decrease parallel with an increase in the number of operations. The gram-positive bacteria were responsible for most of the SWI. Although the depth of SWI is difficult to clinically predict, the presence of bacteremia suggests the existence of mediastinitis. Despite their lesser clinical importance, the superficial infections carry a long postoperative stay.

[The protection of an internal mammary artery graft with a tubular prosthesis made of polytetrafluoroethylene]. / Protección del injerto de arteria mamaria interna con prótesis tubular de politetrafluoroetileno.

A polytetrafluoroethylene tubular prosthesis was used to protect an internal mammary artery graft in a patient with high risk of reoperation. This technique was used to avoid the risk of damage of the graft and to reduce the difficulties of the injection of cardioplegia during the reoperation procedure. The usefulness of this technique is discussed in the article.

Spontaneous left atrial haematoma.

We present a woman with paroxysmal atrial fibrillation and a mass in the left atrium. Cross-sectional echocardiography defined the lesion as cystic, while magnetic resonance imaging depicted it as a solid mass with areas of focal bleeding. Surgical resection showed a partially organized haematoma within the left atrial wall. The patient did well after surgery, although atrial fibrillation recurred. The presence of an atrial haematoma is rare, specially when spontaneous, and we stress the usefulness of magnetic resonance in reaching an aetiologic diagnosis.